body{
    padding: 0;
    margin: 0;
    background-color: #282C34;
    color: #CCCCCC;
    text-align: center;
}
h2{
   padding: 1% 0%;
   user-select:none; -webkit-user-select:none;/*取消复制功能*/
}
#main{
   margin: 10% 5% 0% 5%;
   background-color: #21252B;
}